,-*

0

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PROVINCE OF BRITISH CO

MINISTRY OF TRANSPORTATION AND

PAVEMENT DESIGN

STANDARDS (TECHNICAL CIRCULAR T - 9/95) m

GEOTECHNICAL AND MATERIALS ENGINEERING BRANCH

JULY 10,1995

Technical Circular T - 9/95 (July, 1995)

TO: REGIONAL MANAGERS, GEOTECHNICAL & MATERIALS ENG. REGIONAL MANAGERS, OPERATIONS REGIONAL MANAGERS, PROFESSIONAL SERVICES REGIONAL MANAGERS, PAVING REGIONAL ASPHALT LABORATORY SUPERVISORS

SUBJECT: PAVEMENT DESIGN STANDARDS

1.0 PURPOSE 2.0 BACKGROUND 3.0 PROCEDURE

3.1 3.2

3.3 3.4

3.5 3.6

TABLE 1 TABLE 2 TABLE 3

TABLE 4 TABLE 5

FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5

PAVEMENT DESIGN STANDARDS MINJMUM SELECT GRANULAR SUBBASE (S.G.S.B.) REQUIREMENTS 3.2.1 ROCKSUBGRADES 3.2.2 SOIL SUBGRADES TRAFFIC ANALYSIS AMERICAN ASSOCIATION OF STATE HIGHWAY AND TRANSPORTATION OFFICIALS (AASHTO) PAVEMENT DESIGN CRITERIA ALTERNATIVE PAVEMENT DESIGNS RESPONSIBILITIES

TABLES

PAVEMENT DESIGN STANDARDS: TYPES "A" & PAVEMENT DESIGN STANDARDS: TYPE "C" & ESAL CALCULATIONS MODIFIED ASPHALT INSTITUTE METFXOD C.G.E. FACTORS - NEW CONSTRUCTION C.G.E. FACTORS - PAVEMENT REHABILITATION

"B" "D"

FIGURES TYPE "A" - HIGH VOLUME ROADS TYPE "B" - MEDIUM VOLUME ROADS TYPE "C" - LOW VOLUME ROADS TYPE "D" - SUBDIVISION ROADS TAC CANADIAN VEHICLE WEIGHTS AND DIMJ3NSIONS STUDY LOAD EQUIVALENCY FACTOR (ESAL) VS AXLE GROUPLOAD

PAGE

1 2 3 3

3 3

10 11

14 15 18

4 5

12 16 17

13

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T DESIGN ST-

1.0 PYBPOSE:

The purpose of this technical circular is to define pavement design standards for new construction and reconstruction in the Province of British Columbia

The standards defme the requirements for all pavement structures designed by British Columbia Ministry of Transportation and Highways personnel, private consultants and contractors. These standards have been developed in consultation with British Columbia Regional Pavement Designers.

Four design standards, based on general roadway classification, are used to categorize British Columbia's provincial road network. Twenty (20) year design Equivalent Single Axle Loads (ESALs) are the primary criteria used for selection of the appropriate standard with additional subgrade material criteria applied to low volume roads and subdivision roads. These are summarized as follows:

STANDARD ROADWAY TYPE DESIGNATION

20 YEAR DESIGN ESAL CRITERIA

TYPE "A" HIGH VOLUME ROADS

TYPE " B MEDIUM VOLUME ROADS

TYPE "C" LOW VOLUME ROADS

TYPE "D" SUBDIVISION ROADS

> 1,000,000

100,000 to 1,000,000

< 100,000

< 100,000

1.0 PURPOSE (c-:

The new standards specify the thicknesses of Asphalt Pavement (A.P.) and Crushed Base Course (C.B.C.). The structural requirements for Select Granular Sub-base (S.G.S.B.) thickness are to be determined by the pavement designer based on traffic loading, subgrade type and local environmental conditions (drainage conditions and frost penetration). In addition to structural requirements, minimum thicknesses of Select Granular Sub-base S.G.S.B. (Reference: Section 3.2) must be met.

Where specific site conditions and economic benefits warrant departure from the pavement design standards specified herein, Crushed Granular Equivalency (C.G.E.) factors are provided for development of alternative pavement designs.

It is the intent that the standards specified herein replace those currently specified in the,Ministry of Transportation and Highways (M.O.T.H.) "Design Manual" (Reference: TAB 3Part B - Cross Sections and Barrier Drawings for Low Volume Roads, Rural Local Undivided, Rural Collector and Arterial, RED and RFD).

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2.0 BACKGROUND:

Over the last decade, British Columbia pavement designs on primary highways have changed from relatively thin pavement layers consisting of 75 mm of dense graded Asphalt Pavement (A.P.) placed on Crushed Base Course (C.B.C.) and Select Granular Sub-base (S.G.S.B.) layers to current standards that designate 50 mm of dense graded Asphalt Pavement (A.P.) over 100 mm of Asphalt Base Course (A.B.C.) over Crushed Base Course (C.B.C.) and Select Granular Sub-base (S.G.S.B.) layers.

s Due to typically high asphalt cement contents (ranging from 4.0% to 5.0%) in the Asphalt Base Course (A.B.C.), the intended function of this layer to serve as a crack relief layer has been negated. The resultant 150 mm asphalt slab thickness has posed some problems during subsequent rehabilitation due to the difficulty of restoring pavements with cracks and other distress types that have propagated the full depth of the asphalt mat. In some cases, such as on the Coquihalla Highway, the use of Class "C" asphalts, the most temperature susceptible grade specified in the Canadian General Standards Board (C.G.S.B.) standards, have amplified the situation with a high frequency of transverse cracking that has occurred due to cold winter temperatures.

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2.0 w: Rehabilitation measures such as Hot In-Place (H.I.P.) recycling, which treat only the top 50 mm of the Asphalt Pavement (A.P.), are ineffective in preventing reflective cracking in thick asphalt slabs, since full depth cracks may be up to 150 mm in depth. Cold milling can retard the reflection of lower layer cracks in an asphalt pavement surface overlay; however, it necessitates the removal of most of the original asphalt pavement slab (i.e. up to 125 mm of a 150 mm thick pavement) at great expense.

o The new pavement design standards incorporate the application of thinner asphalt pavements. Therefore, the pavement structure is generally cheaper to build, resulting in a more economical structure that can be rehabilitated effectively in the future at less cost.

3.0 PROCEDURE:

3.1 PAVEMENT DESIGN

The new pavement design standards, replacing those cunently specified in the Ministry of Transportation and Highways (M.O.T.H.) "Design Manual", are summarized in Tables 1 and 2 and illustrated with typical cross-sections in Figures 1, 2,3 and 4.

s The structural requirements for Select Granular Sub-base (S.G.S.B.) thickness are to be determined by the pavement designer based on traffic loading, subgrade type and local environmental conditions (drainage conditions and frost penetration). The minimum Select Granular Sub-base (S.G.S.B.) requirements specified herein shall apply.

3.2.1. ROCKSUBGRADES

150 mm minimum Select Granular Sub-base (S.G.S.B.) on Rock Subgrades.

All levelling materials applied directly to blasted rock cuts shall be of Select Granular Sub-base (S.G.S.B.) quality.

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TABLE - 1

PAVEMENT DESIGN STANDARDS

100 mm A.P. 150 mm C.B.C. (-25 mm)

150 mm C.B.C. (75 mm MAXIMUM Size) S.G.S.B. (As required in Soil - * Minimum 300 mm Thickness)

S.G.S.B. (150 mm in Rock) **

TYPE "B" (XEFERENCE: FIGURE 2) UM VOLUME w: 100.000 to 1.000.000 I

75 mm A.P. * 150 mm C.B.C. (-25 mm)

150 mm C.B.C. (75 mm MAXIMUM Size) S.G.S.B. (As required in Soil - * Minimum 300 mm Thickness)

S.G.S.B. (150 mm in Rock) **

NOTES: 15 mm AS. specified in Type "B" shall be constructed in 2 liftr for 19 mm MAXIMUM size nggregate and 1 lift for 25 mm MAXIMUM size aggregate (in neeordance with the latest version of B.C. MOTH Standard Specifications for Highway Construction - Seetion 223, Subsection 223.23.06).

No S.G.S.B. is required in exceptional circumstances where the following criterin bnve been met:

Structural Design Criteria is satisfied

AND

Subgrade material consists of clean granular deposits that satisfy S.G.S.B. grndation and construction criteria (i.e. rutting criteria) in nccordnnce with the latest version of B.C. MOTH Standard Specificntions for Highway Construction -Section 202 "GRANULAR SURFACING, BASE AND SUBBASES", Subsection 202.06).

** All levelling materinls applied directly to blasted rock cuts shall be of S.G.S.B. quality.

* THE FMAL S.G.S.B. THICKNESS MUST BE APPROVED BY THE REGIONAL GEOTECHNICAL AND MATERIALS ENGINEER

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TABLE - 2

0

PAVEMENT DESIGN STANDARDS

TYPE "C" (REFERENCE: FIGURE 3)

< ~ 0 0 . 0 0 0 ~ I -

50 mm A.P. 225 mm C.B.C. (-25 mm)

S.G.S.B. (As required in Soil - * Minimum Requirements Specified Below) S.G.S.B. (150 mm in Rock) **

50 mm A.P. 225 mm C.B.C. (-25 mm)

S.G.S.B. (As required in Soil - * Minimum Requirements Specified Below) S.G.S.B. (150 mm in Rock) **

NOTES: "Minimum 150 mm S.G.S.B. on Coarse Grained Subgrades (Unified Soils Classification System -

GWlCPlGM/GC/SWlSP/SM/SC) where groundwater does not pore a drainage problem and frost penetration dou not affect the structure.

6 Minlrrmm 300 mm S.G.S.B. on Fine Grained Subgrades (Unified Soils Classification System - MucL/oumm/cH/oH).

No S.G.S.B. is required in exceptional circumstances where the following criteria have been met:

Structural Design Criteria is satisfied

AND

Subgrade material consists of clean granular deposits that satisfy S.G.S.B. gradation and construction criteria (i.e. rutting criteria) in accordance with the latest version of B.C. MOTH Standard Specifications for Highway Construction -Section 202 "GRANULAR SURFACING, BASE AND SUB-BASES", Subsection 202.06).

** All levelling materials applied directly to blasted rock cuts shall be of S.G.S.B. quality.

THE FINAL S.G.S.B. THICKNESS MUST BE APPROVED BY THE REGIONAL GEOTECHNlCAL AND MATERIALS ENGINEER

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FIGURE - 1

ui e ui

TYPE "A"

HIGH VOLUME ROADS > 1,000,000 ESAL *s

NOTES:

S No S.G.S.B. is required in exceptional circumstances where t h e following cr i te r ia have been met:

S t ruc tu ra l Design Cri ter ia is satisfied and

Subgrade mater ia l consists of clean granular deposits t h a t sa t i s fy S.G.S.B. grada t ion a n d construction cr i ter ia k e . ru t t i ng cr i ter ia) in accordance wi th the l a t e s t version of t h e B.C. MOTH Standard Specifications for Highway Construction - Section 202 "GRANULAR SURFACING, BASE AND SUB-BASES", (Subsection 202.06).

**All levell ing mater ia l s applied directly to blasted rock c u t s sha l l be of S.G.S.B. qua l i ty .

' THE FINAL S.G.S.B. THICKNESS MUST BE APPROVED BY THE REGIONAL GEOTECHNICAL AND MATERIALS ENGINEER.

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FIGURE - 2

0

0

150 nm 01 25 rnrn C.B.C.

S.G.S.B. 300 N MINIMUM in So1 *LSee notes below1

TYPE "B"

MEDIUM VOLUME ROADS 100.000 t o 1,000.000 ESAL's

NOTES 75 mm A.P. t o be constructed in 2 lifts for 19 m m MAXIMUM size aggregate and 1 lift for 25 m m MAXIMUM size aggregate. (In accordance with the latest version of the B.C. MOTH Standard Specifications for Highway Construction - Section 223, Subsection 223.23.061

No S.G.S.B. is required in exceptional circumstances where the following criteria have been met:

Structural Design Criteria is satisfied and

Subgrade material consists of clean granular deposits t ha t satisfy S.G.S.B. gradation and construction criteria L e . rutt ing criteria) In accordance with the latest version of the B.C. MOTH Standard Specifications for Highway Construction - Section 202 "GRANULAR SURFACING, BASE AND SUB-BASES", (Subsection 202.06).

**All levelling materials applied directly to blasted rock cuts shall be of S.G.S.B. quality.

T H E FINAL S.G.S.B. THICKNESS MUST BE APPROVED BY T H E REGIONAL GEOTECHNICAL AND MATERIALS ENGINEER.

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FIGURE - 3

0

L 5 0 mm AP. 225 mm of 25 mm C.E.G. *S.G.S.B. (See notes Wow)

TYPE "C" LOW VOLUME ROADS

< 100,000 ESAL's NOTES:

Minimum 150 mm S.G.S.B. on Course Grained Subgrades (Unified Soils Classification System - GW/GP/GM/GC/SW/SP/SF/SC) where groundwater does not pose a drainage problem and frost penetration does not affect t h e s t ruc ture .

Minimum 300 mm S.G.S.B. on Fine Grained Subgrades (Unified Soils Classification System - ML/CL/OL/MH/CH/OH).

* No S.G.S.B. is required in exceptional circumstances where t h e following cr i te r ia have been met:

S t ruc tura l Design Criteria is satisfied and

Subgrade mater ia l consists of clean granular deposits t h a t sa t i s fy S.G.S.B. gradat ion and construction cr i ter ia (i.e. ru t t i ng cr i ter ia) in accordance wi th the la tes t version of the B.C. MOTH Standard Specifications for Highway Construction - Section 202 "GRANULAR SURFACING, BASE AND SUB-BASES", (Subsection 202.06).

Minimum 150 mm S.G.S.B. i n Rock.

All levelling mater ia l s applied directly t o blasted rock c u t s shall be of S.G.S.B. qual i ty .

REGIONAL GEOTECHNICAL AND MATERIALS ENGINEER. THE FINAL S.G.S.B. THICKNESS MUST BE APPROVED BY THE

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FIGURE - 4

U e

0

50 mm A.P. 225 mm of 25 rnm C.B.C. 4.G.S.B. (See notes below1

TYPE "D"

SUBDIVISION ROADS <100,000 ESAL's

NOTES * Minimum 150 mm S.G.S.B. on Course Grained Subgrades (Unified Soils

Classification System - GW/GP/GM/GC/SW/SP/SM/SC) where groundwater does not pose a drainage problem and frost penetration does not affect t h e s t ructure .

Minimum 300 mm S.G.S.B. on Fine Grained Subgrades (Unified Soils Classification System - ML/CL/OL/MH/CH/OH).

No S.G.S.B. is required in exceptional circumstances where t h e following cr i te r ia have been met:

S t ruc tura l Design Criteria is satisfied and

Subgrade mater ia l consists of clean granular deposits t h a t sat isfy S.G.S.B. gradat ion a n d construction c r i te r ia 1i.e. r u t t i n g cr i ter ia) in accordance wi th t h e la tes t version of t h e B.C. MOTH Standard Specifications for Highway Construction - Section 202 "GRANULAR SURFACING, BASE AND SUB-BASES", (Subsection 202.06).

Minimum 150 mm S.G.S.B. in Rock.

All levelling mater ia ls applied directly t o blasted rock cu t s shal l be of

THE FINAL S.G.S.B. THICKNESS MUST BE APPROVED BY THE S.G.S.B. qual i ty .

REGIONAL GEOTECHNICAL AND MATERIALS ENGINEER.

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3.2 -SELECT GRANULAR SUB-BasE S.G.&JL

3.2.2 mJT, S U B G W

The following minimum Select Granular Sub-base (S.G.S.B.) thickness requirements on Soil Subgrades shall apply:

(1) Generally, a minimum thickness of 300 mm Select Granular Sub-base (S.G.S.B.) shall be applied over subgrade materials.

(2) No Select Granular Sub-base (S.G.S.B.) is required in exceptional circumstances where the following criteria have been met:

Structural Design Criteria is satisfied

Ah!D

Subgrade material consists of clean granular deposits that satisfy Select Granular Sub-base (S.G.S.B.) gradation and construction criteria (i.e. rutting criteria) in accordance with the latest version of British Columbia Ministry of Transportation and Highways Standard Specifications for Highway Construction - Section 202 "GRANULAR SURFACING, BASE AND SUB- BASES", (Subsection 202.06).

(3) All final Select Granular Sub-base (S.G.S.B.) thicknesses must be approved by the Regional Geotechnical and Materials Engineer.

GNS-S-TYPES C & D I 1 11 I t II

(1) Generally, minimum thickness requirements for Select Granular Sub-base (S.G.S.B.) shall be based on subgrade material type as follows:

. Mlnlmum 150 mm Select Granular Sub-base (S.G.S.B.) on Coarse Grained . . Subgrades (Unified Soils Classification System - GW/GP/GM/GC/SW/SP/SMSC) where groundwater does not pose a drainage problem and frost penetration does not affect the structure.

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(1) (continued)

300 mm Select Granular Sub-base (S.G.S.B.) on Fine Grained Subgrades (Unified Soils Classification System - ML/CL/OL//MH/CWOH).

(2) No Select Granular Sub-base (S.G.S.B.) is required in exceptional circumstances where the following criteria have been met:

Structural Design Criteria is satisfied

ANLl Subgrade material consists of clean granular deposits that satisfy Select Granular Sub-base (S.G.S.B.) gradation and construction criteria (i.e. rutting criteria) in accordance with the latest version of British Columbia Ministry of Transportation and Highways Standard Specifications for Highway Construction 1995 -Section 202 "GRANULAR SURFACING, BASE AND SUB-BASES", (Subsection 202.06).

(3) All final Select Granular Sub-base (S.G.S.B.) thicknesses must be approved by the Regional Geotechnical and Materials Engineer.

3.3

The recommended method for determination of 20 year design Equivalent Single Axle Loads (ESALs) is the Modified Asphalt Institute Method specified in Table 3. Furthermore, it is recommended that in the application of this method, ESALs for various truck axle codigurations are determined based on the Transportation Association of Canada (TAC) Vehicle Weights and Dimensions Study, illustrated in Figure 5 (ESALs vs Axle Group Load).

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TABLE - 3

a

ESAL CALCULATIONS MODIFIED ASPHALT INSTITUTE METHOD

ESAL = AADT * HVP * HVDF * NALV * TDY

where:

ESAL ' = EQUIVALENT SINGLE AXLE LOADS PER LANE PER YEAR (FOR THE BASE YEAR)

AADT = AVERAGE ANNUAL DAILY TRAFFIC (ALL LANES & BOTH DIRECTIONS)

HYP = HEAVY VEHICLE PERCENTAGE (DIVIDED BY 100)

HVDF = HEAVY VEHICLE DISTRIBUTION FACTOR (% OF HEA VY VEHICLES IN THE DESIGN LANE)

NALV = NUMBER OF EQUIVALENTAXLE LOADS PER VEHICLE (ESAL 's PER VEHICLE)

TDY = TRAFFIC DAYS PER YEAR

NQZE ESALs (BASE YEAR) X 20 YR. TRAFFIC GROWTH RATE FACTOR = 20 YEAR DESIGN E S A h

g . . . . . . . . . . . . . . . . . . . . . . . .;.

8 . . . . . . . . . . . .

7 . . . . . . . . . . . .

6 . . . . . . . . . . . .

9 8 5 . . . . . . . . . . . .

s e 4 . . . . . .

E

u 4 LL

> u

e

2s'

3

3 . . . . . .

2 i, ......

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1 ... . . . . . . . . . . . . . . . . . . . . . . . .

0 0 5

. . . . . . .

. . . . . . .

. . . . . . . . ., . . . . . . . .

. . . . . . . . . . . . . . / . . . . . . . . . . . . . . // ...... . . . . . . . . . . . . . . . . . . . . . . . . . ~- /

r .

. . . . . . .

....................... /

I I I I 10 15 20 25

AXLE GROUP LOAD (kg X 1000)

7

6

5

4

3

2

1

0

-STEERING SINGLE 1 TANDEM - TRIDEM

linistry of Transportation and Highways EOTECHNICAL and MATERIALS ENGINEERING

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3.4 -ION OF 0) PA- -

In order to ensure a consistent design approach using the American Association of State Highway and Transportation Officials (AASHTO) Pavement Design Method for new construction, the following criteria shall apply:

8 ANALYSISPERIOD = 20YEARS

s RELIABILITY (R):

HIGH VOLUME & MEDIUM VOLUME ROADS: R = 85% LOW VOLUME & SUBDIVISION ROADS: R = 75%

0 STANDARD DEVIATION (So): So = 0.45

s PAVEMENT SERVICEABILITY INDEX QSI):

INITIAL SERVICEABILITY INDEX (pi) = 4.2 TERMINAL SERVICEABILITY INDEX (pt) = 2.5

s MATERIALS CHARACTERIZATION:

MATERIAL DESCRIPTION

RESILIENT STRUCTURAL MODULUS * (MR) LAYER MPa (approx. psi) COEFFICIENT

(ai)

ASPHALT PAVEMENT (A.P.) 2,750 (400,000)

CRUSHED BASE COURSE (C.B.C.) 200 (30,000) (25 mm, 50 mm & 75 mm)

SELECT GRANULAR SUB-BASE (S.G.S.B.)

100 (15,000)

0.40

0.14

0.10

* IF FIELD OR LABORATORY RESILIENT MODULUS VALUES (MR) ARE AVAILABLE, THEY MAY BE USED. HOWEVER, THEY MUST BE APPROVED BY THE REGIONAL GEOTECHNICAL AND MATERIALS ENGINEER

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DRAINAGE COEFFICIENTS (mi):

The following drainage coefficients (mi) shall apply to untreated Crushed Base Course (C.B.C.) and Select Granular Sub-base (S.G.S.B.) materials:

mi CRUSHED BASE COURSE (C.B.C.)/SELECT GRANULAR SUB-BASE (S.G.S.B.) DESCRIPTION

1.15 OPEN GRADED CRUSHED BASE COURSE (C.B.C.) & SELECT GRANULAR SUB-BASE (S.G.S.B.)

0 0.95 HIGH QUALITY CRUSHED BASE COURSE (C.B.C.)

(i.e. 6% FINES PASSING .075 mm SIEVE) & SELECT GRANULAR SUB-BASE (S.G.S.B.)

0.80 POOR QUALITYCRUSHED BASE COURSE (C.B.C.)

(i.e. ~ 5 % FINES PASSING .075 mm SIEVE) & SELECT GRANULAR SUB-BASE (S.G.S.B.)

3.5 ALTERNATIVEPAVE-

Where site specific conditions warrant (i.e. granular quality, granular availability, etc.) alternative pavement designs may be generated using the Crushed Granular Equivalency (C.G.E.) concept w. The economic benefit of any alternative design (minimum practical thicknesses are to be maintained) is to be determined on a project specific basis.

C.G.E. factors for New Construction and Pavement Rehabilitation are provided in Tables 4 and 5 respectively.

Dynatest ELMOD software is acceptable for rehabilitation overlay design. However, ELMOD is not to be used for design of new construction.

I

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TABLE - 4

CRUSHED GRANULAR EQUIVALENCY (C.G.E.) FACTORS NEW CONSTRUCTION

Hot-Mix Asphalt Pavement (A.P.) B.C. Stabilizer Open Graded Granular Base (Bituminous Bound) Asphalt Base Course (A.B.C.) Recycled Asphalt Pavement In Granular Base Course (Mii. 50% Aggregate)

P Portland Cement Concrete Roller Compacted Concrete Cement Treated Base Open Graded Granular Base (Cement Bound)

0

2.0 1.5 I S * * 1.7 0.5*

3.0 2.5 1.8 1.6

Unbound -d Base C-. -50 mm & -75 @ Well Graded Crushed Unbound Granular Base 1 .o Intermediate Graded Crushed Unbound Granular Base Open Graded Crushed Unbound Granular Base

M o u n d Granular Sub-base Lwm Well Graded Crushed Unbound Granular Sub-base Intermediate Graded Crushed Unbound Granular Sub-base Open Graded Cmhed Unbound Granular Sub-base Pit Run Granular Sub-base Screened Granular Sub-base

1.1** 1.2**

1.0 1.18' 1.2** 0.7 0.7

* **

Based on British Columbia Ministry of Transportation and Highways experience. Based on British Columbia Ministry of Transportation and Highways experience and must be confined with a minimum of 75 mm of dense graded Asphalt Pavement (A.P.).

(1) SURFACE TREATMENT: For design, surface treatment is assumed to have no structural strength. Built-up layers of surface treatment (>75 nun thickness) could be assigned a C.G.E. of 1.5.

(2) GEOTEXTILES AND GEOGRIDS: Geotextiles do not provide structural strength and are to be used only as separators. Geogrids can be used to provide structural equivalence if strain can be mobilized within the grid.

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us B o u n d b y m Hot-Mix Asphalt Pavement (uncracked) Hot-Mix Asphalt Pavement (cracked) Hot In-Place Recycled Asphalt Pavement

TABLE - 5

2.0 1.5 1.7*

0

CRUSHED GRANULAR EQUIVALENCY (C.G.E.) FACTORS PAVEMENT REHABILITATION

P I Portland Cement Concrete (good condition) Portland Cement Concrete (fair condition) Portland Cement Concrete (poor condition) Cement Treated Base

Unbound GrElnulzlr Base and Sub-base Old Granular Base Old Granular Sub-base (Crushed)

I

3.0 2.5 2.0 1.5

0.7 0.7

* The C.G.E. for Hot In-Place (H.I.P.) Recycled Asphalt Pavement is lower than virgin material due to an expected reduced fatigue life.

** Based on British Columbia Ministry of Transportation and Highways experience.

NOTES: (1) SURFACE TREATMENT: For design, surface treatment is assumed to have no structural strength. Built-up layers nf surface ITeatment (>75 mm thickness) could be assigned a C.G.E. of 1.5 (uncracked) and 1.1 (cracked).

(2) GEOTEXTILES AND GEOGRIDS: Geotextiles do not provide structural strength and are to be used only as separators. Geogrids can be used to provide siructural equivalence if strain can be mobilized within thc grid.

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3.6 RESPONSIBILITIES

0

rn In accordance with Section 3.5, Altemative Pavement Designs are to be communicated to the Pavement Design Engineer, Geotechnical and Materials Engineering Branch in Victoria for review prior to tendering.

Any future modifications to the PAVEMENT DESIGN STANDARDS specified herein shall be coordinated and issued by the Pavement Design Engineer, Geotechnical and Materials Engineering Branch in Victoria. Any future modifications will be developed in consultation with Regional Pavement Designers.

CONTACT:

A. Aderichin, P. Eng. Pavement Design Engineer Geotechnical and Materials Engineering Branch (Victoria) (604) 387-7708

C.C. A.D.M. Highway Operations C.C. C.C. All Regional Directors

A.D.M. Planning & Major Projects

J.L.S. Buckle, P. Eng. NChief Highway Engineer